Most of the trip insurance policies exclude coverage for pre-existing condition, but will waive them IF you purchase the insurance within seven days of first putting down $ on the trip. For people with pre-existing conditions that they are worried about during the trip (such as myself with AIDS), this can be an important consideration.
OTOH, I still don't worry about insurance when I'm traveling within the "first world" - I figure that if I'm well enough to leave the US, the likelihood of problems is remote enough and going to a hospital in, say, Amsterdam wouldn't be the end of the world. Besides, the policies tend to be too expensive relative to the costs of my trips.
But for Egypt, you bet I bought the insurance!